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Rangarajan, Sathish

Chemistry

2005

MS

A comparison of the relative effects of two stereocenters on the diastereoselectivity of the addition of a vinyl synthon to chiral alpha-hydroxy hydrazones under neutral radical cyclization conditions is presented. Tandem thiyl addition/cyclization upon a Silicon-tethered vinyl group, followed by treatment with tetrabutylammonium fluoride accomplished a one-pot vinylation process to afford acyclic anti-hydrazino alcohols as major products. It was found that the use of the auxiliary had almost no effect on the 1,2-diastereoselectivity of the process. The endocyclic stereocenter was thus concluded to play a dominant role in this cyclization pathway.